The subject Invention relates to an adjustment mechanism for adjusting various components of a vehicle, particularly a seat.
Adjustment mechanisms are widely used in automotive vehicles for adjusting a variety of components such as window panes, headrests, armrests, seat backs and seat cushions. Many prior art adjustment mechanisms incorporate complicated ratchet and pawl mechanisms and/or gear arrangements. Examples of such adjustment mechanisms are shown in U.S. Pat. Nos. 4,634,182, 4,696,515 and 4,705,319. These adjustment mechanisms utilize a large number of moving parts which adds to the overall cost and weight of the vehicle. In addition, the adjustment mechanisms have a higher propensity for failure and need for replacement of parts.
The prior art has also contemplated the use of coil springs within the adjustment mechanisms to move between a release position and a locking position. The coil springs use frictional forces to secure the component being adjusted. An example of such a coil spring adjustment mechanism for a seat cushion is shown in U.S. Pat. No. 4,533,027. The ""027 patent has a coil spring coupling an input shaft to an output shaft. The input shaft is directly connected to an actuation handle. The range of rotation for the output shaft is directly proportional to the range of rotation for the actuation handle. Accordingly, when the seat cushion is being adjusted, the handle remains is an actuated position. An example of a coil spring adjustment mechanism for a seat back recliner is shown in U.S. Pat. No. 5,163,736. The ""736 patent utilizes the coil spring to hold the recliner in a desired position. The recliner incorporates additional parts to provide the adjustment and the user must push the seat back to recline the seat back rearward.
The prior art coil spring adjustment mechanisms require additional parts, require that the user assists in the adjustment, and/or have a limited range of motion. Accordingly, it is desirable to have an adjustment mechanism which utilizes a coil spring for providing an unlimited range of adjustment and does not require any additional parts or a user to initiate the adjustment. In addition, the adjustment mechanism should be capable of adjusting in both a rotational and a counter rotational direction.
A mechanism adjusts a relative position of a component within the vehicle. The mechanism has a mounting bracket. A drive drum is mounted rotatably on the bracket for providing a rotary output to adjust the component. An actuation handle is rotatably mounted to the drive drum and rotatable relative to the drive drum from a neutral position. A coil spring surrounds the drive drum in a sliding engagement. A return spring assembly engages the coil spring. The handle engages the coil spring and the return spring assembly. As the handle is rotated from the neutral position, the coil spring is rotated in a winding sense about the drive drum and against the return spring thereby coupling the handle and the drive drum for rotation. As the handle is counter rotated towards the neutral position, the return spring assembly urges the coil spring to rotate in an unwinding sense, uncoupling the handle from the drive drum.
Accordingly, the subject invention utilizes a coil spring and provides for an unlimited range of adjustment in either rotational direction. The subject adjustment assembly does not require any additional parts or a user to initiate the adjustment. The adjustment assembly operates to ratchet the component being adjusted. In other words, the adjustment assembly grasps the component, moves the component and then releases the component and returns to the original position such that the adjustment assembly may grasp the component again if desired. This xe2x80x9cratchetingxe2x80x9d operation may continue until the component is moved into a desired position.